NAME

       posix_openpt - open a pseudoterminal device

SYNOPSIS

       #include <stdlib.h>
       #include <fcntl.h>

       int posix_openpt(int flags);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       posix_openpt(): _XOPEN_SOURCE >= 600

DESCRIPTION

       The posix_openpt() function opens an unused pseudoterminal master device, returning a file
       descriptor that can be used to refer to that device.

       The flags argument is a bit mask that ORs together zero or more of the following flags:

       O_RDWR Open the device for both reading and writing.  It is usual to specify this flag.

       O_NOCTTY
              Do not make this device the controlling terminal for the process.

RETURN VALUE

       On success, posix_openpt() returns a nonnegative  file  descriptor  which  is  the  lowest
       numbered  unused descriptor.  On failure, -1 is returned, and errno is set to indicate the
       error.

ERRORS

       See open(2).

VERSIONS

       Glibc support for posix_openpt() has been provided since version 2.2.1.

CONFORMING TO

       posix_openpt() is part of the UNIX 98 pseudoterminal support (see pts(4)).  This  function
       is specified in POSIX.1-2001.

NOTES

       The  posix_openpt()  function  is  a recent invention in POSIX.  Some UNIX implementations
       that support System V (aka UNIX 98) pseudoterminals don't have this function,  but  it  is
       easy to implement:

           int
           posix_openpt(int flags)
           {
               return open("/dev/ptmx", flags);
           }

       Calling  posix_openpt()  creates  a  pathname  for  the corresponding pseudoterminal slave
       device.  The pathname of the slave device can be obtained  using  ptsname(3).   The  slave
       device pathname exists only as long as the master device is open.

SEE ALSO

       open(2), getpt(3), grantpt(3), ptsname(3), unlockpt(3), pts(4), pty(7)

COLOPHON

       This  page  is  part of release 3.54 of the Linux man-pages project.  A description of the
       project,    and    information    about    reporting    bugs,    can    be    found     at
       http://www.kernel.org/doc/man-pages/.

                                            2012-04-20                            POSIX_OPENPT(3)